Stepper motor drivers or Ardunio stepper motor drivers

[Doddy]

The Arduino-based controllers/drivers have been designed around the original 3d-printer designs, capable of driving the small NEMA-17 stepper drivers which provide relatively low torque. The firmware on the boards is limited, but optimised to this role with an incomplete G-code interpreter and limited in terms of the rate of step-generation. There is an element of these being "new" technology applied to new tech devices, vs the legacy controllers, as well as something that was once fairly basic but which is maturing with development/use and with a growing user base.

Higher power CNC machines require higher torque (=power) steppers, running at higher currents and voltages. For these individual stepper drivers are preferred and these offer better capability and higher resolution (not necessarily accuracy) with micro-step generation. Behind this, it's generally preferred to host a more capable and complete controller.

You can find examples of cards that sit between these - with high-power drivers integrated onto controller cards. These are generally frowned upon - high energy systems can suffer failures (as can the lower power machines of course) allowing components to be replaced (or upgraded) rather than replacing the system.

You could use the shield-boards, you could even hay-wire "proper" stepper-drivers from such a board if you so desired. That's your decision to make. The shields have a sort-of-advantage that it removes an element of complexity (and control) from the tool-chain in terms of the machine controller - that's all exported to the shield; in the more conventional design that controller is provided by PC-based software such as Mach/UCCNC etc.

I know/understand the shield-based designs, I use the same microcontrollers for any number of things. However, for my use-case (CNC lathe and milling machines), I'll stick with seperate controllers, drivers, etc.